Method of fabricating a magnetic flux channel for a transverse wound motor

Abstract

Methods of fabricating a magnetic flux channel for a transverse wound electric motor by forming a ring of plural adjacent molded magnetic flux channel pole pieces and a second ring of opposite pole pieces. The two rings are mated such that each pole piece mates with an opposite pole piece to form magnetic flux channels and a c-shaped recess forms a winding channel for a transverse phase winding. After mating, the rings are bonded together to form a stator assembly of the transversely wound electric motor. The two rings may be approximately identical, or the two rings may be different as long as they mate to form the plural molded magnetic flux channels and the transverse phase winding channel. The molds may be designed to form the outer surface of a stator assembly. Molds of adjacent phases may be combined back-to-back to reduce part count and increase mechanical strength.

1. A method of fabricating a magnetic flux channel for a direct drive parallel pole transverse wound electric motor comprising the steps of:
 forming a first ring of plural adjacent molded magnetic flux channel first pole pieces, the plural adjacent pole pieces forming a first c-shaped recess, a top portion of first each pole piece having a width less than the width of a base portion and a length approximately double the length of the base portion for an approximately equal cross sectional area; 
 forming a second ring of plural adjacent molded magnetic flux channel second pole pieces the second ring a mirror image of the first ring, the plural adjacent pole pieces forming a second c-shaped recess, a top portion of first each pole piece having a width less than the width of a base portion and a length approximately double the length of the base portion for an approximately equal cross sectional area to decrease magnetic flux leakage and fringing; 
 mating the first and the second ring, each first pole piece mating with one of the second pole pieces with a gap between the top portion of the first and the second pole pieces to form the magnetic flux channel with each of the first and the second pole piece having an opposite polarity to capture flux of each rotating magnet when incorporated into the direct drive parallel pole transverse wound electric motor and the first and second c-shaped recesses mating to form a winding channel for housing a transverse phase winding; and 
 bonding the first and the second ring with a bonding agent to form a stator assembly of the direct drive parallel pole transversely wound motor, wherein when the current through the transverse phase winding reverses the first and second parallel pole pieces switch polarity. 
 
   
   
     2. The method of  claim 1 , wherein the step of forming a first ring and a second ring comprises the steps of:
 creating a first three-dimensional mold for forming the first ring of plural adjacent molded magnetic flux channel first pole pieces; and 
 creating a second three-dimensional mold for forming the second ring of plural adjacent molded magnetic flux channel second pole pieces, the first and second three-dimensional molds forming a stator structure of the transverse wound electric motor. 
 
   
   
     3. The method of  claim 2 , wherein the step of creating a first three-dimensional mold and a second three-dimensional mold, comprises the steps of:
 defining an outer dimension and geometry of the Molded Magnetic Flux Channel; and 
 building the first and second three-dimensional mold with a 3-D rapid prototyper, or by using Direct Digital Manufacturing. 
 
   
   
     4. The method of  claim 2 , wherein the step of creating a first and a second three-dimensional mold comprises the step of:
 using a lost wax casting to create the first and second three-dimensional mold. 
 
   
   
     5. The method of  claim 2 , further comprising the step of:
 using the first and second first three-dimensional molds with the first and second ring of plural adjacent molded magnetic flux channel first and second pole pieces, respectively, as the stator assembly of the transversely wound electric motor to provide additional electrical insulation for the transverse phase winding and control the magnetic shape and the magnetic air gap of the completed motor/dynamo. 
 
   
   
     6. The method of  claim 2 , wherein the step of creating a first three-dimensional mold for forming the first ring and second ring of plural adjacent molded magnetic flux channel first and second pole pieces each further comprises the step of:
 forming an alignment protrusion on an exterior surface the plural first and second pole pieces forming an interior perimeter of the first and second ring, wherein when the first and second ring align the magnetic flux channel with a hub of the transversely wound electric motor/dynamo. 
 
   
   
     7. The method of  claim 6 , further comprising the step of:
 calculating an offset according to 360/divided by the number of pole pieces/divided by a number of phases in a multiphase motor/dynamo; and 
 offsetting the alignment protrusions to produce a predetermined electrical phase difference between phases of the multiphase transversely wound electric motor. 
 
   
   
     8. The method of  claim 6 , further comprising the step of:
 calculating a mechanical offset by dividing 360 by one-half of a number of poles per phases in a multiphase motor to produce a quotient; 
 dividing the quotient by a number of phases of a multiphase motor to produce the mechanical offset; and 
 offsetting the alignment protrusions to produce degrees of mechanical offset between phases of the multiphase transversely wound electric motor. 
 
   
   
     9. The method of step  2 , further comprising the step of:
 designing each one of the first and second three-dimensional molds as an outer shell of the stator assembly. 
 
   
   
     10. The method of  claim 2 , further comprising the step of:
 forming each molded magnetic flux channel first and second pole piece to have a rounded exterior surface opposite the c-shaped recess to prevent magnetic debris from entering the structure and a gap between mated first and second pole pieces. 
 
   
   
     11. The method of  claim 2 , further comprising the steps of:
 determining a dimension of a transverse phase winding; and 
 forming the c-shaped recess interior surface of the first and second ring to the dimensions of the transverse phase winding. 
 
   
   
     12. The method of  claim 1 , wherein the stop of forming a first and second ring of plural adjacent molded magnetic flux channel first and second pole pieces, respectively, includes the step of:
 forming a set of pie-shaped female molds of molded magnetic flux channel for assembly into a complete ring. 
 
   
   
     13. The method of  claim 1 , wherein the mating of the first and second pole pieces form an air gap between the upper first and second pole pieces, the distance between interior interleaved opposing surfaces of the first and second magnetic body members forming the channel being approximately four times larger than the air gap between the upper north first and second pole pieces. 
   
   
     14. The method of  claim 13 , wherein forming the first and second ring of adjacent first and second pole pieces, respectively includes:
 forming the interior facing surface of the first and second pole pieces to have an undercut face to reduce magnetic leakage between mated pole pieces. 
 
   
   
     15. The method of  claim 1 , wherein forming the first and second ring of adjacent first and second pole pieces, respectively includes:
 forming the interior facing surface of the first and second pole pieces to have an undercut face to reduce magnetic leakage between mated pole pieces.